## Search found 21 matches

Tue Dec 05, 2017 10:49 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Sig Figs in Calcs
Replies: 1
Views: 187

### Re: Sig Figs in Calcs

From the textbook, pg 472: "The number of digits following the decimal point in a pH value is equal to the number of significant figures in the corresponding molar concentration, because the digits preceding the decimal point simply report the power of 10 in the data (as in log 105 # 5)."
Tue Dec 05, 2017 10:46 pm
Forum: Lewis Acids & Bases
Topic: Identifying Oxides as Acidic or Basic (12.17)
Replies: 1
Views: 189

### Re: Identifying Oxides as Acidic or Basic (12.17)

From the textbook, pg 469: "Metals form basic oxides, nonmetals form acidic oxides; the elements on a diagonal line from beryllium toward polonium and several d-block metals form amphoteric oxides."
Tue Dec 05, 2017 10:43 pm
Forum: Identifying Acidic & Basic Salts
Topic: HF
Replies: 4
Views: 390

### Re: HF

From the textbook, page 485: "The weaker the H-A bond, the stronger the acid. This effect is dominant for acids of the same group" Since F and Cl are in the same group, the one with the weaker bond will be a stronger acid. Cl is less electronegative so it will have a weaker bond and theref...
Tue Dec 05, 2017 5:50 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Strong Acids/Bases
Replies: 3
Views: 277

### Strong Acids/Bases

Do strong acids have a Ka? Do strong bases have a Kb?
Tue Dec 05, 2017 4:44 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pH in changing temperature
Replies: 4
Views: 488

### pH in changing temperature

Would the pH of pure water increase or decrease with increasing temperature? Does this mean that pure water is acidic/basic at temperatures other than 25 C or that the entire pH scale is different at other temperatures? Thanks
Thu Nov 16, 2017 8:31 pm
Forum: Lewis Structures
Topic: Lone Pairs
Replies: 2
Views: 258

### Re: Lone Pairs

Thank you for the answer, but I actually figured out that hybridization answers the question I was actually trying to ask. The placement of the electrons in lewis structures of single atoms makes more sense in those terms than by looking at the regular electron configuration.
Sun Nov 05, 2017 2:45 pm
Forum: Lewis Structures
Replies: 3
Views: 243

What's the difference between a biradical and a molecule where one atom has a lone pair on it?
Thu Nov 02, 2017 2:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Order of subshells
Replies: 1
Views: 244

### Order of subshells

When is 4s higher energy than 3d and vice versa?
What does that mean for what order you write them in when writing e- configurations? What about for the order for the "exceptions" like Cu? And does that affect what order you take electrons out to make ions (like for Co2+ for instance)?
Thu Nov 02, 2017 2:13 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity and Ionization Energy
Replies: 1
Views: 211

### Electron Affinity and Ionization Energy

Why is it that electron affinity can be positive or negative but ionization energy is always positive?
(I asked this in discussion and my TA suggested I post it here, but I know there probably won't be an easy answer)
Thu Nov 02, 2017 2:10 pm
Forum: Lewis Structures
Topic: Lone Pairs
Replies: 2
Views: 258

### Lone Pairs

In terms of quantum/e- config, what exactly are lone pairs? For instance, in carbon, the e- configuration is https://files.mtstatic.com/site_4334/102843/0?Expires=1509660165&Signature=Ymjob8lBg3GwutP2Ar3iNGqgJG~Zkmzhi5ez71N4Rb7qZd2wM4dWhA~vaiLPqpNyNxjU9k6m3r4Y7uLkSaxfOSmd8WC9TZQOW0wRKHhYeqoIbbhN...
Thu Oct 26, 2017 9:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Difference between subshell and orbital [ENDORSED]
Replies: 9
Views: 1584

### Re: Difference between subshell and orbital[ENDORSED]

In the textbook, page 39 - "There are three p-orbitals in each subshell" Based on this, you can connect the terminology to the different quantum numbers (not their number or meaning, but what they refer to in terms of the shape) n = energy level or shell (for example the n=1 energy level) ...
Thu Oct 26, 2017 9:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodes
Replies: 4
Views: 403

### Nodes

Can anyone explain the relation between nodes of a wavefunction and the nodal planes on the orbitals? In particular there is a paragraph in the textbook on page 39 that basically says "each wavefunction has n-1 nodes" and next to that paragraph there is an illustration of the shape of p su...
Thu Oct 26, 2017 3:42 pm
Forum: Ionic & Covalent Bonds
Topic: covalent bond
Replies: 7
Views: 667

### Re: covalent bond

A bond only involves two atoms, but a molecule with more atoms can have covalent bonds between pairs of the atoms within it.
Thu Oct 26, 2017 3:40 pm
Forum: Lewis Structures
Topic: S and P blocks and Lewis structures [ENDORSED]
Replies: 4
Views: 409

### S and P blocks and Lewis structures[ENDORSED]

Since Lewis structures are based on octets, does this mean we only use them for s and p blocks? Or maybe only for the first few periods? Are they applicable/useful for elements with d orbitals?
Thu Oct 26, 2017 3:35 pm
Forum: Trends in The Periodic Table
Topic: Transition Metals
Replies: 3
Views: 274

### Transition Metals

I think in class he mentioned something about the name "transition metals" for the d-block having to do with their e- configuration and properties. Does anyone know what he said about what "transition" means?
Thu Oct 26, 2017 3:33 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity and Ionization Energy
Replies: 4
Views: 539

### Re: Electron Affinity and Ionization Energy

If it helps, you can think of them as conceptually opposites. "Ionization energy is the energy needed to remove an electron from an atom in the gas phase. Electron affinity is the amount of energy that is released or acquired when an electron is added to an atom in the gas phase" sounds li...
Mon Oct 16, 2017 12:33 am
Forum: Photoelectric Effect
Topic: General Q about photoelectric effect terms [ENDORSED]
Replies: 2
Views: 251

### Re: General Q about photoelectric effect terms[ENDORSED]

To build on that, the energy of the photon is how much energy goes into system, but it can be more or less (or the same) as thee threshold energy. It's unrelated. But if you're given the kinetic energy or velocity of the electron afterwards, you can use that and the threshold energy to find the ener...
Mon Oct 16, 2017 12:15 am
Forum: Photoelectric Effect
Topic: Determining the Series [ENDORSED]
Replies: 3
Views: 330

### Re: Determining the Series[ENDORSED]

The name of the series is based on which energy level n the electron drops down to at the end (not which one it started from at the top). So if it drops down to n=1 it's the Lyman series. Also n=1 is the lowest so it wouldn't make sense for there to be a series for electrons dropping from n=1.
Thu Oct 05, 2017 10:00 pm
Forum: Empirical & Molecular Formulas
Topic: Combustion Analysis
Replies: 5
Views: 415

### Re: Combustion Analysis

If it's combustion of a hydrocarbon it will be C and H for sure. If you're given the products of the combustion you can assume that all the elements other than oxygen are for sure in the combusted substance. If the mass of all the elements other than oxygen in the products is less than the given mas...
Thu Oct 05, 2017 9:30 pm
Forum: Significant Figures
Topic: Integers and Exact Numbers- Sig Figs [ENDORSED]
Replies: 4
Views: 493

### Re: Intergers and Exact Numbers- Sig Figs[ENDORSED]

It means that when you multiply or divide given numbers you have to base the sig figs on the measured numbers that were given to you. You can never be more accurate than the measurements given/the measuring tools you use, so you can't have more sig figs in your answer (when multiplying/dividing) tha...
Thu Oct 05, 2017 9:20 pm
Forum: Limiting Reactant Calculations
Topic: M. 15 Fundamentals
Replies: 4
Views: 508

### Re: M. 15 Fundamentals

It looks like your question is about how to write chemical formulas when it's not given in problems like this. I don't think we're going to be asked to do that on tomorrow's test but I'll answer you anyways in a very simple way (just enough to get by). Ions of elements in group 17 (which CL is in) h...